Numerous hammer safety mechanisms of various types are known in the prior art.
While many of these prior mechanisms usually operate in a satisfactory manner, serious injury can occur if there is a minor malfunction, or mishandling which causes accidental and/or unexpected firing.
Among the causes of such accidental firing with known safety mechanisms are mishandling such as dropping or bumping the firearm so inertial forces release a cocked hammer, direct impact on a decocked hammer, accidentally pulling the trigger just far enough to release the hammer, and slipping of the hammer as is it being cocked or decocked.
Mechanical malfunctions such as wear, corrosion, or failure of various parts of the firing mechanism can also cause unexpected firing.
Further, some of the prior safety mechanisms make the firearm unreliable so it will not fire when it is intended to shoot, and many of the prior mechanisms have fragile parts subject to hammer impact, or wear quickly, so the firearm soon becomes useless.